1. Field of the Invention
The invention relates to an X-ray system of the type having a patient examination table, an image acquisition unit underneath the surface of the patient examination table (such as a flat detector), and an X-ray generator mounted above the table.
2. Description of the Prior Art
An X-ray system of this described type is a typical so-called “overtable system”. Such an overtable system usually is controlled by means of a main control console located outside the X-ray examination room. The operator can watch the patient through a glass wall between the control room and the X-ray examination room, and interacts with the patient via a voice communication system. In addition to overtable systems, so-called “undertable systems” also are known, in which the X-ray generator is located underneath the table and the image acquisition unit, usually an image intensifier or a fluorescent screen, is mounted above the patient examination table. In the undertable system, the operator is directly present with the patient and, therefore, can touch and/or turn the patient during the imaging or X-ray. During the procedure, the operator is protected from X-ray radiation by lead-lined rubber gloves and a lead-lined apron or a lead coat, as well as by appropriate shielding equipment mounted on the patient examination table. In both versions, the image data can be transmitted from the image acquisition unit to an image-viewing screen installed beside the table or at the control console. During the examination, the operator can view the images immediately. Undertable and overtable systems each have their own advantages and disadvantages. The substantial advantage of an undertable system is the availability of direct contact with the patient during the examination. The advantage of the overtable system consists in the fact that the operator has better radiation protection. Another basic advantage of the overtable system is its superior image geometry, because the distance of the detector-focus in relation to the object-focus distance is better than in the undertable system. This automatically results in a better image quality. Whether an undertable or an overtable system is used for a certain examination depends on the type of examination as well as on the “examination philosophy” of the particular physician, which is usually determined by his/her education history.
A system disclosed in PCT Application WO 02/15198 has a C-arm, with the X-ray generator being located underneath the patient examination table.
U.S. Pat. No. 5,900,638 also describes an X-ray diagnostic device located above the patient examination table so that the X-ray generator must be located underneath the table.
In order for physicians in a consulting room or a clinic to have the option of obtaining images using either the undertable procedure and the overtable procedure, at the present time both an undertable and an overtable systems must be available, and usually are installed in different rooms. It is clear that an installation with several imaging devices—especially if these instruments are up-to-date, including expensive dynamic flat detectors—is very costly. Although, generally the various devices can be used in parallel practice shows that, in a joint consulting room, for example, several physicians use the overtable system for their examinations, whereas the undertable system is not sufficiently utilized (or vice versa). Thus, a rational utilization of the systems with a simultaneous reduction of the waiting times requires costly planning and scheduling of examinations. In some cases—especially in emergency cases—this planning must be overridden. Thus, the result is that, at least temporarily, these instruments are not optimally used and, on the contrary, the staff and the patients face unnecessary waiting times.